In conventional automation networks, which can comprise a plurality of control devices for controlling components of an automation system, cryptographic keys are provided to the control devices for carrying out a cryptographic security function. Cryptographic keys of this type are frequently manually configured, that is, a value for the respective cryptographic key is input by means of an input mask. The cryptographic keys are included, for example, in a configuration file or are input via a configuration tool. The cryptographic security function which a cryptographic key offers depends on the length and entropy of the cryptographic key used. The longer the cryptographic key used and the higher the entropy thereof or the randomness of the characters used therein, the greater, in principle, is the strength of the cryptographic protective function achieved by the cryptographic key. For example, a long cryptographic key with a large number of special characters offers relatively high cryptographic protection.
A disadvantage of such long cryptographic keys which also use special characters is that said keys are difficult for the person inputting the cryptographic key to memorize and that the input of the cryptographic key also takes a relatively long time. Therefore, in many cases, despite the low protective effect provided by a short key with low entropy, short keys which are easily memorized and usually have low entropy are nevertheless used for a variety of cryptographic security functions. This applies, in particular, to technicians who undertake manual configurations on control devices of an automation network. If the system requires the input of strong or long keys with many special characters, many users also tend to note down in writing on pieces of paper cryptographic keys that are difficult to memorize in order to read them again and, for example, to input them into an input mask. In the case of long cryptographic keys or passwords having high entropy or randomness in the characters used, faulty input or incorrect typing often occurs when the cryptographic keys or passwords are input.